View source for 128.4 Pavement Rehabilitation Projects for Freeways

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'''<u><center>Pavement Rehabilitation Guide</center></u>'''
* [http://library.modot.mo.gov/RDT/reports/Ri00008/Brf02013.pdf Summary 2003]
* [http://library.modot.mo.gov/RDT/reports/Ri00008/RDT02013.pdf Report 2002]
* '''See also:''' [https://www.modot.org/research-publications Research Publications]
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The district prepares a [https://epg.modot.org/forms/CM/4R_CONCEPTUAL_STUDY_REPORT.docx 4R Conceptual Study Report] for all resurfacing, restoration, rehabilitation and reconstruction (4R) projects on interstates and freeways. Part I of the 4R Report is also needed for a pavement design thickness determination for any major route in which full depth reconstruction is being considered. Part I of the form is completed and submitted to the Construction and Materials Division, with a copy to the Design Division, in order to initiate the pavement rehabilitation analysis or pavement thickness determination.  

Construction and Materials will issue a Pavement Type Selection (PTS) letter to the district and provide a copy to Design. Upon receipt of the PTS letter, the district will complete Part II of the form. The district will prepare an estimate of the paving and non-paving costs for each alternate provided in the PTS letter. The completed 4R report (Parts I and II) is submitted to the Design Division, with a copy to the Construction and Materials Division.

The submittal of the 4R report to the Design Division is accompanied, if necessary, by a request for any [[131.1 Design Exception Process|design exceptions]] that may be required for the project. All 4R projects are designed to current interstate design criteria (since the "4th R" stands for "reconstruction"). These criteria are found in the following EPG locations:
: [[230.1 Horizontal Alignment]]
: [[230.2 Vertical Alignment]]
: [[:Category:231 Typical Section Elements for Roadways|231 Typical Section Elements for Roadways]]
: [[:Category:232 Facility Selection|232 Facility Selection]]
: [[:Category:233 At - Grade Intersections|233 At – Grade Intersections]]
: [[:Category:234 Interchanges|234 Interchanges]]
: [[236.13 Designing Right of Way Plans|236.13 Designing Right of Way Plans]]
: [[:Category:748 Hydraulics and Drainage|748 Hydraulics and Drainage (for Bridge and Drainage issues]])

Justification for varying from these criteria must be submitted as a design exception.

All [[:Category:123 Federal-Aid Highway Program#123.1.1 FHWA Oversight - National Highway System|"non-exempt" projects]] require federal oversight and require the approval of the conceptual study report by the FHWA. After review of the information and approval of the requested design exceptions by the State Design Engineer, the Design Division will submit Parts I and II of the 4R report, the rehabilitation analysis, and all costs (paving and non-paving) to FHWA for approval. Upon approval by FHWA, the Design Division will send copies of the approval letter to the district and Construction and Materials by the Design Division along with copies of the approved documents.

Design exceptions for non-exempt projects will also require approval of FHWA. Once approved by the State Design Engineer, the design liaison engineer will submit all design exceptions to FHWA for approval. After FHWA approval, the Design Division will forward a copy of the approved design exception to the district.

The requirements of [[:Category:104 Scope|EPG 104 Scope]] cause identification of needs and the development of solutions to occur early in the project development process. Because of the time delay between scoping of a project and actual construction, significant changes to the pavement condition including accelerated pavement deterioration may occur which can make the original scoped pavement rehabilition strategy inapproporiate.

For these reasons, Construction and Materials is asked to review the original pavement rehabilitation strategy, provided with the 4R report, once the construction dollars for the project fall within one or two fiscal years beyond the current year of the STIP. Any significant changes in project data or pavement condition is also provided. The purpose of this review will be to ensure that the correct rehabilitation strategy is being used to address the pavement deficiency. This re-evaluation is conducted in a time frame that will allow any necessary adjustments to the estimated cost to occur prior to the inclusion of the construction funds in the current year of the STIP.

Should there be a need to change the recommended strategy, an approval process similar to that for the original 4R report will need to be followed for the revised strategy. This may include re-submission to the FHWA, if applicable.

==128.4.1 Project Information==
Any deficiencies, in addition to those included in the originally identified need, that require correction are explained in the letter of transmittal.

==128.4.2 Traffic Data==
The designer [https://modotgov.sharepoint.com/:b:/r/sites/tp/Shared%20Documents/Traffic%20Collection/Request%20Forms%20-%20Traffic%20Forecast%20-%20Road%20User%20Costs/Traffic%20Forecast%20Request%20Form.pdf?csf=1&web=1&e=G0Npik requests traffic data] from Transportation Planning or the TMS database.

==128.4.3 Existing Pavement Data==
If the district elects to recommend a rehabilition option to Construction and Materials for approval, then the Strategic Highway Research Program manual (publication FHWA-RD-03-031) titled "Distress Identifications Manual for the Long-Term Pavement Performance Project" is used to describe the pavement distress. The pavement distress type and severity is documented. Any drainage issues are also documented. The amount of [[:Category:613 Pavement Repair|pavement repair]] is also estimated and included in the submittal.

Any items that might restrict the addition of pavement thickness to the existing traveled way are noted. These might include drainage structures, curbing, median barriers, right of way restrictions, or other special conditions.

The [[media:128 Straight Line Profile of Exiting Pavement.pdf|straight line profile]] identifies the location of all bridges, including overpasses, by log mile and station, and indicates at each location the field measured vertical clearances. It also states if the bridge is to be used in place, rehabilitated or reconstructed. An [[media:128 Lane Sketch of Existing Pavement and Proposed Lane Additions.pdf|example of a sketch]] showing existing lanes, additional lanes proposed under the project, and additional lanes programmed in the future is available. The width of the median and location of existing bridges, including overpasses, is also shown on this sketch. The location of each item is identified by log mile.

==128.4.4 Proposed Pavement Data==
The district submits proposed pavement data after the Construction and Materials Division has determined the rehabilitation method. If the district’s proposed pavement rehabilitation method is different than the one recommended by the Construction and Materials Division, justification must be provided.

==128.4.5 Geometric Data==
The horizontal alignment, vertical alignment, and other features of the highway section are compared to adjoining sections. Any items within the clear zone are listed. A [[131.1 Design Exception Process|design exception]], if necessary, is prepared and submitted for approval that reflects the minimum distance to objects in the clear zone.

==128.4.6 Crash Data and Safety Enhancements==
The crash data is obtained from the TMS database. The calculation for the project crash rate is shown in [[:Category:128 Conceptual Studies#128.5 Accident Rate Calculation|EPG 128.5]]. The crash data included in Part II is used to determine whether a special surface needs to be applied to reduce the accident rate. The designer carefully analyzes the crash data. Any unusual circumstances are noted and recommendations for correction made. Safety enhancements such as guardrail or bridge modification, and the need for bicycle/pedestrian facilities are also discussed.

==128.4.7 Construction Sequence, Traffic Control, and Construction Incentives==
The 4R report will contain a discussion of how the construction of the improvement will affect the existing traffic and any recommendations for the construction sequence that will minimize those impacts. A discussion of the traffic control that will be used during construction and the necessity for any construction incentives to shorten the time that normal traffic flow is disrupted is also included in the report.

==128.4.8 Project Cost Data==
The 4R report contains a current estimate of the proposed costs of the improvements. Details on the preparation of project estimates can be found in [[:Category:104 Scope|EPG 104 Scope]].